In the wake of December's Sandy Hook school shootings, the debate over America's gun policy has come to a full boil. And, according to American Spirit Arms, an Arizona gun manufacturer, it has even caused one of the country's biggest banks to take matters into its own hands.

The Aurora, Colo., theater shooting re-energized the national argument on gun control. And whenever that happens, regardless of right, wrong, or the chance of a real national policy shift, gun sales tend to rise in the near term. And that presents an investing opportunity.

In the movie "A Christmas Story," Ralphie had his sights set on just one gift: a Red Ryder BB gun. But many Americans this season clearly had heavier arms on their minds: Background checks on gun buyers hit a single-month record in December.